Comparison of Midazolam Plasma Concentrations in ARDS Patients with and Without ECMO Support-Prospective...

Patients undergoing ECMO therapy have a much higher need for drug therapy due to the increased volume of distribution and deeper levels of sedation. The influence of ECMO support on the achieved midazolam concentrations is unknown.

This prospective, single-center study was conducted between October 2022 and December 2024. All mechanically ventilated patients with an FiO₂ over 0.6 or requiring VV ECMO for respiratory support were included. Patients younger than 18 years, patients without midazolam infusion, and patients with a do-not-resuscitate protocol were excluded. Patients were divided into a group requiring ECMO therapy (group A, n = 14, 88 measurements) and a group receiving conventional respiratory support (group B, n = 11, 44 measurements). Mean daily doses of midazolam and achieved midazolam concentrations were compared. Chi-squared tests, Mann-Whitney U tests, Pearson's r correlation, and Spearman's rank correlation were used to assess statistical significance between groups, where appropriate.

In terms of demographic data, patients in group A were comparable to group B, except that patients in group A had a lower BMI (25.7 ± 5.1 kg/m² vs. 34.0 ± 10.1 kg/m², p = 0.014). Midazolam requirements in the ECMO group were higher (3.6 ± 1.6 mg/kg vs. 1.8 ± 1.3 mg/kg, p < 0.001). Despite this, midazolam plasma concentrations in both groups were comparable, and only midazolam metabolites were found to be higher in group A (60 ± 72 ug/L vs. 22 ± 19 ug/L; p < 0.001).

The use of probably higher doses of midazolam does not translate into higher plasma midazolam concentrations in ECMO patients.